The present invention relates to an active vibration isolating support apparatus which bears the load of a vibrating unit and suppresses the transmission of vibration by driving an actuator to extend and contract on a predetermined cycle with a current which corresponds to a primary vibration of the vibrating unit through control by a control unit.
An active vibration isolating support apparatus or active vibration isolating support apparatus is known in Patent Document No. 1 below which supports an engine on a body of an automobile and suppresses the transmission of primary vibration of the engine by supplying a sinusoidal current for an actuator so as to displace the actuator in a sinusoidal fashion.
[Patent Document No. 1]
JP-A-2002-139095
Incidentally, engine vibrations include, in addition to a primary vibration having a period corresponding to the number of cylinders, vibrations of higher order than the primary vibration such as a secondary vibration and a tertiary vibration. However, since the suppression of such higher-order vibrations is not taken into consideration in the aforesaid conventional active vibration isolating support apparatus, there has been caused a problem that a sufficient vibration isolating effect cannot be obtained.
In addition, while it is considered that both the primary vibration and the higher-order vibration are suppressed by driving the actuator of the active vibration isolating support apparatus with a target current resulting by combining a primary target current which cancels the primary vibration and a higher-order target current which cancels the higher-order vibration, since phases of the primary vibration and the higher-order vibration deviate from each other, even in the event that a minimum value of the primary target current is made to be 0, a then minimum value of the higher-order does not become 0. Consequently, a minimum value of the target current resulting from the combination of the primary target current and the higher-order target current does not become 0, leading to a possibility that a direct current component rides on the target current to thereby increase the heat release value of the actuator wastefully.